A known challenge in the fencing industry that wooden fence posts often need to have their top ends cut down after the post is cemented into the ground or otherwise anchored in place, for example to keep uniformity in the relative height of the post in comparison to rails or picket boards of the fence from post to post along the fence line. This trimming of fence posts is sometimes conducted using handheld power tools without any guide means for providing an accurate cut. For example, attempts to cut a flat horizontal top end are often ‘eyeballed’ without any measurement or marking prior to the cut, often resulting in departure from a true horizontal plane. Even where careful measurement and marking of the desired cutting plane is performed beforehand, wandering of the blade or unsteadiness of the tool operators hand can nonetheless result in deviation from the intended cutting plane.
Further complication arises in that many hand tools lack sufficient blade dimensions to cut fully through the thickness of a typical size fencepost in a single cut. For example, the cutting depth of a handheld circular saw in relation to the fencepost may be insufficient depending on the particular saw and post sizes concerned, thus requiring that the operator cut into the post from multiple sides of the post, and the typical accuracy expected from such cuts will result in a slight offset between the height of the two cuts, resulting in an non-flat finished cut that either needs sanding or other further processing, or leaves an unsightly appearance in the finished fence installation.
U.S. Pat. No. 4,889,329 discloses a prior art post cutting jig intended to address another known problem that since the post are often not truly square (i.e. deviating from precise 90° corners), attempted cuts guided by the post surfaces or by visible cut lines drawn onto the same can also result in deviations from the desired cutting plane. The prior art invention uses four guide members that fasten to one another to form a four-sided jig that closes fully around the fence post, whereby a circular saw can be used to cut partially through the post from multiple sides thereof to eventually cut fully through the post. The top edges of the guide members form a guide along which the fence of the circular saw rides to make a level cut at a distance above the jig. However, the closed nature of this jig (i.e. its full circumference around the post in abutment against all sides thereof when installed) means that the same jig cannot be used on posts of different sizes. Accordingly, a jig purchased by a user can only be employed on posts or lumber of a single predetermined size.
U.S. Patent Application Publication No. 2006/0289085 discloses a guide for cutting elongated workpieces in which a pair of matching templates are fixed together in a face-to-face relationship with one another across an empty space between them, and aligned slots in the two templates provide guide paths for a saw blade. The fixed nature of the connection between the two templates gives the guide a four-sided closed form, which allows easy installation by slipping of the guide over the end of a workpiece and tightening of a screw on one of the templates against the workpiece, but the guide is limited in the size of workpiece on which it can be applied due to the fixed positional relationship between the two templates. In addition, the screw mechanism holds the respective template at a spaced distance outward from the side of the workpiece in the event that the workpiece thickness is notably less than the fixed distance between the two templates, and the tip of the single screw mechanism is the only contact point of the guide on this side of the workpiece. This may potentially lead to relative movement between the workpiece and the guide, and thus potentially reduce the reliability or accuracy of the guide.
PCT Application Publication No. WO2006/008538 teaches another slip-on, closed four sided post-cutting guide with blade-receiving slots in opposing walls or templates of the guide, the design of which is intended for a single predetermined post size, and is incapable of use on a larger post or workpiece.
French Patent Application 2975616 discloses another closed four-sided cutting guide with blade-receiving slots, again having the slot-equipped walls or templates set a fixed predetermined distance apart from one another with no flexibility to accommodate workpieces of greater dimension.
French Patent 2148947 shows another closed four sided cutting guide with slots in opposing walls thereof, but appears to have the slots arranged for cutting longitudinally or axially of the workpiece, rather than for making cross-cuts that transverse the longitudinal axis of the workpiece.
PCT Application Publication No. WO2009/153602 teaches a saw guide in the form of a cutting block having a principle bore for receiving a tubular workpiece to be cut, a sighting bore that opens radially into the principal bore for viewing of a cut-position marker on the tube, and a cutting slot lying axially of the sighting bore and normally of the principle bore. The cutting block closes fully around the principle bore, meaning that the saw guide is of a slip-on type having a fixed maximum size it can accommodate. While the reference does teach that the same unit can be used on smaller sizes, it requires the addition of a bushing of appropriate size in the principle bore in order to maintain a good fit of the guide on the smaller workpiece.
U.S. Pat. No. 4,608,898 discloses a combined protractor and saw guide that defines a track in which the slide plate of a saber saw (also commonly referred to as a jig saw) can run to follow a selected angle of the track that is set using the protractor. The track resides on one side of the workpiece, but there is no further guidance of the blade on the other side of the workpiece. Accordingly, it may be possible for the blade to wander from a true cut. In addition, a conventional saber saw has an insufficient blade length to cut through larger workpieces, such as a 4×4-inch post commonly employed for fence construction. Accordingly, this leads again to the need to cut such a workpiece from multiple sides, making a clean, flat, even cut very difficult to achieve.
Another cutting template that provides guidance on only one side of the workpiece in question is shown in U.S. Pat. No. 4,273,016, but is specifically designed for the purpose of trimming the bottom of a door to lie parallel to a floor with enough clearance for a subsequently added floor covering layer. Accordingly, the cutting template is not well suited to address the needs of a fence post cutting application.